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H. R. RICARDO.

BALANCING OF RECIPROCATING ENGINES. APPLICATION FILED MAR-4.1919

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v Patented July 15, 1919.

2 SHEETS-SHEET l.

H. R. RICARDO.

BALANCING 0F RECIPROCATING ENGINES.

APPLICATION FILED MAR. 4, I9I9.

1,31 0,090. Patented July 15, 1919.

' 2 SHEETSSHEET 2.

HARRY' RICARDO, OF LQN'DON, ENGLAND.

' To all u il w m it may concern Be it known that "l, HARRY RALPH RI- OARDO, subject 'ofthe King of England, and residing at London, in England, have invented certain new and useful Improvements in the Balancing of Reciprocating Engines, of which the following is a specification.

This invention relates to the balancing of reciprocating engines of the type having one or more cylinders'which act on a crank shaft with a single throw crank and has for its object to enable not. only the primary but also the secondary forces to be adequately balanced. ve 1 According to thisinvention two masses are mounted so that'they ican-reciproca' substantially radially with relation to the crank shaft and these masses are disposed in line with either side. of the crank and on thatside of the crank shaft which is remote from the cylinder or cylinders.' Two crank tively mounted on the crank shaft. The eccentrics are connected to a pair ofweights which are constrained by links or rocking arms so as to reciprocate substantially radially with relation to the crank shaft. The ratio of the throw of each eccentric to the distance between the center ofthis. eccentric and the center of gravity of the weights to which the eccentric is connected is equal to the ratio of the throw of the main crankto the length of the piston connecting rod.

' Further the ratio between the weight of the masses that are reciprocating, that is to say' the piston and connecting rod on the one side of the crank shaft and the counter weights on the other side thereof, must be inversely proportional to the strokes through which these masses reciprocate. Conveniently two rocking arms are. employed to control the reciprocating movement of the weights and each oil these arms is pivotally connected at one end to the weight at a oint at or near the center of gravity or the weight, At its other end each rocking arm is pivoted to some fixed point situated to ward one side of the crank shaft.

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' specif cation of Letters katent. Patented July 15, E919.

Application an March a, 1919. Serial in. 280,638. a

The accompanying drawings illustrate diagrammatically and by way of example one the view being taken from the end of the v crank shaft and lines being drawn through the centers to illustrate the ratios of the pa -1 s i Fig. 2 is apart sectional elevation ofthe same engine the crank shaft being shown in side elevation and other parts in section on a plane-cutting the crank shaft axis.

Likeletters indicate like parts throughout the drawings. h

The piston Arecipr'ocates in a cylinder B and ,is coupled by a connecting red C to a crank pin D disposed between webs E mounted on a crank shaft E. On the outer side of each web- E is arranged an eccentric G whose strap G is connected to a weight H which is pivotally carried on a pin J at one end of a link K the other end of which'is Qpivoted at L toward one side of the crank shaft on some fixed part for example on the crank case M. The pivot pins J are preferably positioned in the weights G so as to be coincident with the centers of gravity of these weights' The throw 9 of each eccentric G and the distance it between the center of each eccentric and the center of gravity of the weight H to which it is connected are solproportioned in relation to the throw 2 of the main crank and the length 0 of the connecting rod that Further the ratio between the weights of the masses which are reciprocate/d on either side of the crank shaft, that is to say on the one hand the primary masses which comprise the piston A and connecting red C and on 1 the other hand the secondary masses which comprise the counter weights H and links K, mustbe so determined that these weights are inversely proportional to the strokes 6 through which these masses are respectlvely reciprocated.

By thus proportioning the parts in this construction the weights H are reciprocated in opposite phase to the piston and both the primary'and also the secondary disturbing forces willbe balanced. It will be seen that by making the rocking link K of sufiicient length and the throw'g. of the eccentric, that is to say the, stroke of the Weights, relatively short, the are through which the weights are 'reciprocated can be approximated" to a straight line. Other forms of linkage may also be employed which will enable the weights to be reeiprocated substantially raresultant from the use of guides.

Where thej' center of gravity of the main reciprocating mass, that is to say the piston A and connectingrod C, is not coincident with the gudgeon pin but lies at some point in the connecting rod beyond the gudgeon pin so that this center of gravity describes an ellipse instead of a straight line, the conon either side of the mam crank, a pair of struction may be modified so that the center of gravity of each counter weight H-will be elliptical path. This may be effected by concoinpelled to follow a similar and opposing ne'cting the rocking link K to the weight Hat a point slightly below the center of gravity of the weight. In this way the common center of gravity of the two groups of reciprocating masses which are situated on either side of the crank shaft can be maintained coincident with the center of the crank shaft under all circumstances and aperfect mathematical balance can be ob-' tained. 1

The crank webs are conveniently balanced by counter weights E arranged in the usual manner and formed integral with the provided with more than one cylinder if the pistons in all the cylinders act on a single crank pin. ,The details of construction may bemodified to meet requirements.

combination with a crank shaft having a What Iclaim as my invention and to secure by Letters Patent is:

1. In'aninternal' combustion engine the desire single throw crank, a piston reciprocating in a cylinder and connected to this crank,

twomasses which are mounted so that theyl can reciprocate substantially radially wit being disposed one on eitherside of the crank in the axial direction" and at the side .of the shaft remote from the cylinder, and

two crank members mountedoh the crank shaft adjacent to the two crank webs andpiston and othermasses which are thus 'reciprocate'd onW-the opposite sides of the crank shaft being inversely proportional to thestrokes' through which they reciprocate as set forth.

2.- In lai' flinte'rnal combustion engine the combination with a crank shaft having a single throw crank, a piston reciprocating in a .cylidner and connected to this crank, two ec'centrics'mounted on the crank shaft weights respectively connected to these ec-j centrics' and disposed at the side of the single throw crank, a-piston reciprocatmg in acylinder, a connecting rod connecting this piston to the crank, two eccentrics mounted on the crank shaft on either side of the main crank, a pair; of weights respectively connected to these eccentrics and disposed at the side of the crank shaft remote from the piston, the ratio of the throw of each eccentric to the distance between its.

center and the center of gravityv of the weight to which the eccentric is connected being equal to the ratio ofthe throw of the main crank to the length of the piston connecting rod, and two rockingarmseach 1v-,

otall connected atone end to one of the weig ts at or'near its center of: avity and:

at the other. end to a fixed po nt'ysituated toward one side of :the crank asset forth.

In testimony whereof I have signed my 0 name to this specification. relation tothe' crank shaft axis these masses r HARRY RALPH RICARDO.- 

